1. Field of the Invention
The invention relates to a vehicle attitude control system that stabilizes the vehicle behavior.
2. Discussion of Background
U.S. Pat. No. 6,415,215 B1 describes an electronic vehicle attitude control mechanism (electronic stability control) that prevents a sideslip of a vehicle. If a sideslip of the vehicle is sensed when a sudden steering operation is performed or while the vehicle is travelling on a slippery road, the electronic vehicle attitude control mechanism automatically applies brakes to respective wheels individually to stop the sideslip.
The electronic vehicle attitude control mechanism collects information from various sensors which detect, for example, a vehicle speed, a lateral acceleration of the vehicle, and a yaw rate, detects an unstable vehicle state, and then executes, for example, brake control over the individual wheels, and engine output control. In this way, the electronic vehicle attitude control mechanism corrects the travelling direction of the vehicle.
Specifically, when the vehicle understeers, a vehicle yaw moment toward the turning inner side is generated by making the braking force applied to the turning inner wheels larger than the braking force applied to the turning outer wheels. On the other hand, when the vehicle oversteers, a vehicle yaw moment toward the turning outer side is generated by making the braking force applied to the turning outer wheels larger than the braking force applied to the turning inner wheels. In this way, the vehicle behavior is stabilized.
In the related art, in order to detect a vehicle state, a target yaw rate or a target vehicle body sideslip angle is computed based on the information collected from the various sensors. However, an operation amount of a member operated by a driver is not taken into account.